A traditional sunshade umbrella is opened in such a manner of: driving the umbrella rope and the pull lever through an umbrella unfolding crank, and then pushing by hand; such a crank-opening way has the defects of troublesome umbrella unfolding, slow opening speed and high breakage possibility of the umbrella rope; there is another pull lever-type opening and closing device, which, however, is high in umbrella position after pull lever-type closing and also quite inconvenient. In the early Chinese patent of the applicant: Umbrella unfolding and Closing Device (Patent Number: ZL200420107976.0) and the subsequent improved Chinese patent: Umbrella unfolding and Closing Device (Patent Number: ZL200520116792.5), an umbrella unfolding and closing way that is different from the traditional operation ways is adopted, that is, umbrella unfolding and closing are accomplished by sliding the sliding blocks with respect to a post via a knob; this device has better strength and more convenient operation than the traditional ways, but still, it requires manual operation and is more complex in structure.